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Document SA_NOCLDWAIT.

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Make all the SA_* flags go into a tagged list, to improve readability.
This commit is contained in:
Joerg Wunsch 1997-09-13 19:43:24 +00:00
parent 245f17d43c
commit dbf4898f6c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=29341
1 changed files with 38 additions and 17 deletions
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55
lib/libc/sys/sigaction.2
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@ -29,7 +29,8 @@
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" @(#)sigaction.2 8.2 (Berkeley) 4/3/94
.\" From: @(#)sigaction.2 8.2 (Berkeley) 4/3/94
.\" $Id$
.\"
.Dd April 3, 1994
.Dt SIGACTION 2
@ -163,9 +164,10 @@ of the signal are ignored and discarded.
.Pp
Options may be specified by setting
.Em sa_flags .
If the
.Dv SA_NOCLDSTOP
bit is set when installing a catching function
The meaning of the various bits is as follows:
.Bl -tag -offset indent -width SA_RESETHANDXX
.It Dv SA_NOCLDSTOP
If this bit is set when installing a catching function
for the
.Dv SIGCHLD
signal,
@ -173,23 +175,34 @@ the
.Dv SIGCHLD
signal will be generated only when a child process exits,
not when a child process stops.
Further, if the
.Dv SA_ONSTACK
bit is set in
.Em sa_flags ,
the system will deliver the signal to the process on a
.It Dv SA_NOCLDWAIT
If this bit is set when calling
.Fn sigaction
for the
.Dv SIGCHLD
signal, the system will not create zombie processes when children of
the calling process exit. If the calling process subsequently issues
a
.Xr wait 2
(or equivalent), it blocks until all of the calling process's child
processes terminate, and then returns a value of -1 with errno set to
.Dv ECHILD .
.It Dv SA_ONSTACK
If this bit is set, the system will deliver the signal to the process
on a
.Em "signal stack" ,
specified with
.Xr sigaltstack 2 .
If the
.Dv SA_NODEFER
bit is set, further occurrences of the delivered signal are not
masked during the execution of the handler.
If the
.Dv SA_RESETHAND
bit is set, the handler is reset back to
.It Dv SA_NODEFER
If this bit is set, further occurrences of the delivered signal are
not masked during the execution of the handler.
.It Dv SA_RESETHAND
If this bit is set, the handler is reset back to
.Dv SIG_DFL
at the moment the signal is delivered.
.\" Still missing:
.\" .It Dv SA_SIGINFO
.El
.Pp
If a signal is caught during the system calls listed below,
the call may be forced to terminate
@ -369,7 +382,14 @@ The
.Dv SA_NODEFER
and
.Dv SA_RESETHAND
are intended for backwards compatability with other operating systems.
flags are intended for backwards compatability with other operating
systems. The
.Dv SA_NOCLDSTOP ,
and
.Dv SA_NOCLDWAIT
.\" and
.\" SA_SIGINFO
flags are featuring options commonly found in other operating systems.
.Sh SEE ALSO
.Xr kill 1 ,
.Xr kill 2 ,
@ -382,6 +402,7 @@ are intended for backwards compatability with other operating systems.
.Xr sigsetmask 2 ,
.Xr sigsuspend 2 ,
.Xr sigvec 2 ,
.Xr wait 2 ,
.Xr setjmp 3 ,
.Xr siginterrupt 3 ,
.Xr sigsetops 3 ,